Directional antenna



May 12, 1959 HINGs 2,886,813

DIRECTIONAL ANTENNA Filed April 10, 1953 5 Sheets-Sheet 1 fF/GZINVENTOR. DONALD L. HINGS W MM May 12, 1959 D. L. HINGS 2,886,813

DIRECTIONAL ANTENNA Filed April 10, 1953 5 Sheets-Sheet 2 HORIZONTALVERTICAL POLARIZATION POLARIZATION I80 INVENTOR.

' DONALD L.. H/NGS FIG. 9 FIG. IO BY W M f May 12, 1959 D. L. HINGS2,836,813

I DIRECTIONAL ANTENNA Filed April 10, 1953 5 Sheets-Sheet 5 INVENTOR.

DONALD L HIN GS United States Pa n DIRECTIONAL ANTENNA Donald L. Hings,Vancouver, British Columbia, Canada Application April 10, 1953, SerialNo. 347,871

28 Claims. (Cl. 343--819) This invention relates in general todirectional antennas for the higher frequencies, such as VHF, and moreparticularly to a multi-element antenna array having a highly directivepattern in the horizontal plane for a high gain.

At VHF frequencies, the element lengths of antennas are of a practicallength for self-support. A center-fed dipole, which is one-half a wavelength and horizontally polarized, has a figure 8 pattern in thehorizontal plane. By using the Yagi principle of reflectors anddirectors, the directivity of the one-half wave dipole can be increased.The reflectors are typically spaced to the rear of the dipoleapproximately one-quarter wave length of the working frequency and thedirectors are placed in front of the dipole at one-tenth to one-third ofa wave length spacing. Yagi antenna arrays are generally used onfrequencies from ten megacycles to one thousand megacycles.

A plurality of director elements may be used to increase the forwardgain. These directors taper in length, with shorter lengths in the frontto obtain this directivity. The phase relation between the directors anddipole is obtained by cutting the director elements to a length so thatthey are resonant to a frequency higher than the working frequency.Similarly, the reflector element is cut to be resonant to a frequencylower than the working frequency.

An object of the invention is to provide an antenna having a directivepattern.

Another object of the invention is to provide an antenna having a highgain in the forward direction.

Another object of the invention is to provide an antenna having arelatively high front-to-back ratio.

Another object of the invention is to provide a shaded dipoleconstituted by a dipole element and first and second shunt elementshaving resonant frequencies higher and lower than the working frequencyof the dipole.

Another object of the invention is to provide shunt voltage fed antennaelements on a dipole antenna element.

Another object of the invention is to provide collector elements incombination with a shaded dipole wherein the collector elements aregenerally linearly disposed off the ends of the shaded dipole and have aresonant length substantially on the working frequency.

Still another object of the invention is to provide an antenna arraywhich is highly directive and disposed in a fiat plane.

Still another object of the invention is to provide an antenna arrayhaving a driven element and shunt elements each of which have couplingportions for a voltage coupling between the shunt and the drivenelements which voltage coupling may be capacitive or conductive and withthis voltage coupling exceeding the radiation wave coupling achieved bythe space-phase relationship.

Still another object of the invention is to provide an antenna elementhaving a physical length less than the electrical length.

"ice

Still another object of the invention is to provide a driven dipole withboth series and shunt elements, with the series elements beingcollectors disposed off the ends of the driven dipole.

Still another object of the invention is to provide an antenna which iscompact in the front-to-back dimension,, yet which has a gooddirectivity pattern and with a good front-to-back ratio.

Other objects and a fuller understanding of this inven: tion may be hadby referring to the following description A and claims, taken inconjunction with the accompanying drawings, in which:

Figure 1 is a plan view of a driven dipole and a rear wardly disposedsingle shunt element;

Figure 2 is a plan view of a driven wardly disposed shunt element;

Figure 3 is a three dimensional view of a shaded dipole constituted by atuned driven dipole and front and rear shunt elements. M

Figure 4 is a horizontal polar diagram of a radiation pattern of theantenna of Figure 3;

Figure 5 is a plan view of another form of shaded dipole;

Figure 6 is a plan view of another form of a shaded dipole constructedfrom wire;

Figure 7 is a side view of a complete multi-element I antenna system; iFigure 8 is a perspective view of the antennaof Figure 7;

Figures 9 and 10 are horizontal and vertical polarization patterns ofthe antenna of Figures 7 and 8; and

Figure 11 is a plan view of the antenna elements in a modified form ofmulti-element array.

The Figure 1 shows a half wave dipole .15 which in this case isconstructed of metallic tubing approximately one-half inch in diameterfor use on the two hundred megacycle band, and this dipole has beenconstructed twenty-six inches in length. Feeders 16 are connected at thecenter of the dipole 15 and may be either the conventional flexiblelead-in or may be the beginning of a trombone matching stub.

A rear shunt element 17 has a central U-shaped portion 18, diverginglegs 19, and capacitive feet 20. The capacitive feet 20 constitutecoupling portions for the shunt element 17. Areas 21 and 22 on thedipole 15 constitute coupling portions for a voltage coupling with therear shunt element 17.

The Figure 2 shows the dipole 15 in conjunction with a front shuntelement 25. This shunt element has an intermediate portion 26 and legs27. The intermediate portion 26 and legs 27 have generally a U-shape.Capaci-' tive feet 28 are disposed on the ends of the legs 27. The

dipole and a forfeet 28 again are coupling portions of the shunt element25 for voltage coupling with coupling portions on the half wave dipole15 defined by areas 29 and 30. Figures l and 2 thus show two alternativeways of partially shading the dipole 15 by use of the shunt elements 17or 25.

The Figure 3 shows a three dimensional viewof a shaded dipole 31 whichin this case is made of flat bar stock. The shaded dipole 31 includes atuned dipole 32 having a matching transformer 33, a rear shunt element34, and a front shunt element 35. The rear and front shunt elements 34-and 35 have a shape similar to the rear and front shunt elements 17 and25. The rear shunt element 34 has coupling portions 36, and the frontshunt element has coupling portions 37.

The dipoles 15 and 32 have been characterized as driven elements, andthis is taken to mean an antenna element directly connected to some formof radio device, whether receiver or transmitter, since the antennaworks equally well on both receiving and transmitting in accordance.with the usual reciprocity theorem form antennas. The rear shunt element17 or 34 has been tested with a dip meter while in place; and whenhaving its optimum length, it was found that these rear shunt elementshave a resonant frequency characteristic slightly lower than theresonant frequency characteristic. of the dipole or 32 which is at theworking frequency. The front shunt elements and were tested with a dipmeter while in place and found to have a resonant frequencycharacteristic higher than the working frequency. In some cases,depending upon the length of the shunt elements, the end portionsthereof may actually conductively contact the dipoles 15 or 32.Generally, however, capacitive coupling is utilized. This capacitivecoupling is a form of voltage coupling which, because of its closeproximity, is greater than the, space-phase coupling normally associatedwith Yagi directors and reflectors. With reference to Figure 3 it hasbeen found that the spacing between the dipole 32 and the couplingportions 36 and 37 is such that there is. approximately two to threetimes as. great a space at the coupling portions 37 as at the couplingportions 36. The spacing on the rear shunt element 34 was. found to beoptimum at about three-eighths of an inch, and the spacing on the frontelement 35 was found to be optimum at about one inch. At the frequenciesused, this was about .007 of a wave length and .02 of a wave length,respectively. The voltage coupling at the coupling portions 36 and 37,because of this close spacing, is thus greater than the spacephasecoupling which may be considered the radiation wave coupling. Stillfurther, it would be observed that the physical length across the endsof any of the shunt elements is less than the electrical length. It, isbelieved that the impedance across the end portions of the shuntelements is. approximately equal to the impedance on the dipole, such asdipole 15, between the areas 21 and 22, for the rear shunt element 17and between the areas 29 and 30 for the front shunt element 25.

The tested db gain of the antenna of Figure l was about six db gain overa straight dipole. The tested performance of the antenna of Figure 2 wasfound to have about three db gain over a straight dipole. The antenna ofFigure 3, which is a shaded dipole, was found to have seven db over thetuned dipole 32 alone. Feed lines may, of course, be connected onto thematching transformer at the proper impedance matching point as iscustomary practice.

The polar diagram of Figure 4 shows the radiation pattern which is ahorizontal pattern for the plan view of Figure 3. Figure 3 definitelygives a good cardioid pattern toward the. front with a front-to-backratio of approximately 16' db. The shaded dipole of Figure 3 is thus acompact antenna array which has a high forward gain and a stillhigherfront-to-back ratio.

The Figure 5 shows another form of a shaded dipole having a tubular halfwave dipole 4-0 having feed points 41. A front shunt element 42 isformed from tubing and has a plurality of turns on a coil 43. Theelement 42 has coupling portions 44 at the ends thereof. A rear shuntelement 45 is similarly constructed with a coil 46 and coupling portions4-7. By this means the overall length of the front and rear shuntelements was reduced to only about one-eighth wave length, and theoverall thickness of the shaded dipole became about onefifteenth of awave length.

The Figure 6 shows an antenna constructed of wire such as may beutilized for the longer frequencies. A half wave dipole 50, center fedat the feed point 51, is supported by fixed supports 52 and insulators53. A. front shunt element 54 is comprised of a coil 55 and. couplingportions 56 and supported by short lengths of wire 57 broken up byinsulators 58. A rear shunt element 59 similarly includes a coil 6i andcoupling portions 61. An insulating spreader 62 may conven- This showsthat the shaded dipole of .4, iently be used to maintain the coils 55and 60 spaced from the dipole 5d.

The Figures 7 and 8 show a complete antenna array 65. The array 65 ismounted on a mast 66 which carries a horizontal boom 67. A secondhorizontal boom 68 is carried by the boom 67 and vertical booms 69 and7d are carried by the ends of the boom 68. A shaded dipole 71 issymmetrically disposed on the boo-m 67. The shaded dipole 71 includes atuned dipole 72 having a matching stub 73 and front and rear shuntelements 74 and 75, respectively. The shaded dipole 71 is thus similarin configuration to the shaded dipole 31 of Figure 3 or a combination ofFigures 1 and 2. Insulating blocks 76 are fastened to the boom 67 andadjustably clamp the shunt elements 74 and 75 therebetween. This givesan adjustment on the spacing of the coupling portions at the ends of theshunt elements. The tuned dipole 72 is sandwiched between insulatingblocks 77, and these are fastened to the boom 67. The front shuntelement 74 is again found to be resonant to a higher frequency than theworking frequency of the dipole 72, and the rear shunt element 75 isresonant to a lower frequency than the working frequency.

Collector elements 86 and 81 are disposed at the ends of the boom 68 andlie in a horizontal plane. The near ends 82 and 83 are disposed off theends of the shaded dipole 71. The far ends of the collector elements and81 lie forward of the shaded dipole 71. The collector elements 80 and 81therefore are disposed generally linearly off the ends of the shadeddipole 71, and hence, may be considered as series elements relative tothe tuned dipole 72 or shaded dipole 71. By superimposing the horizontalpolar diagram of the shaded dipole shown in Figure 4 upon the top viewof Figure 8 with a maximum forward lobe of the pattern of Figure 4extending forward approximately 1.5 wave lengths, it will be noted thatthe collector elements 80 and 81 are generally parallel to the adjacentportion of the line denoting the field pattern. The fact that the shadeddipole has a cardioid field pattern with parts of the main lobeextending to the rear of the antenna location 88 on Figure 4 makeseffective the use of the collectors 8t) and 81. The collectors 8t) and81 are thereby disposed in the field of the shaded dipole 71 which wouldnot be the case if only a straight dipole were being used with thetypical figure 8 field pattern. Use of the collectors 80 and 81increases the gain from the seven db of the shaded dipole up toapproximately eleven db.

Additional collector elements 84, 85, 86, and 87 are carried on thebooms 69 and 70 above and below the plane of the booms 67 and 68. Thecollector elements 85 and 87 are above the horizontal plane of the booms68 and 67 with the near ends thereof disposed adjacent the ends of thetuned dipole 71. These collector elements slope downwardly toward thecenter as best seen in Figure 7. The collector elements 84 and 86 aredisposed below the boom 63 and slope upwardly so that the near endsthereof are disposed adjacent the tuned dipole 71.

Director elements 90, 91, and 92 of the Yagi type are disposed on theboom 67 in front of the shaded dipole 71. These director elements in theactual case tested were spaced forward of the tuned dipole 72approximately one-third, .57 and .8 of a wave length, respectively. Thedirector elements also tapered in length with the director element 92being the shortest. The total db gain of the, entire antenna array 65was found to be 16.5 db over a straight dipole.

The Figures 9 and 10 show the horizontal and vertical polarizationpatterns, respectively, of the antenna array 65 shown in Figures 7 and8. These polarization patterns. show that the antenna array 65 has anarrow beam both horizontally and vertically with a front-to-back ratioof approximately twenty-three db. The Figure 11 is a plan view ofanother antenna array 95 with. all elements;

disposed in-a horizontal plane. The supporting structure for the variousantenna elements is not shown, but it is understood that such may besimilar to that shown in Figures 7 and 8. A shaded dipole 96 includes atuned dipole 97 and front and rear shunt elements 98 and 99,respectively. A reflector element 100 of the Yagi type is spaced to therear of the tuned dipole 97 in the order of one-quarter wave length. Adirector element 101 is spaced forward of the tuned dipole 97 in theorder of two-thirds a wave length. Collector elements 102 and 103 aredisposed elf the ends of the tuned dipole 97 with these collectorelements lying in the same horizontal plane but with the far ends spacedforwardly of the shaded dipole 96. These collector elements 102 and 103are similar to the collector elements 80 and 81 of the antenna array ofFigures 7 and 8. The collector element 102 has a reflector element 104and a director element 105 spaced rearwardly and forwardly thereof alonga path generally parallel to the path formed by the shaded dipole 96 andthe director 101. Similarly, the collector 103,has a reflector 106 and adirector 107. Again the principal gain over the tuned dipole 97 isachieved by the front and rear shunt elements 98 and 99 which constitutethe shaded dipole and the collector elements 102 and 103. The collectorelements 102 and 103 are disposed serially off the ends of the shadeddipole 96 and are excited therefrom. Since the collector elements 102and 103 are excited, the reflectors 104 and 106 and the directors 105and 107 will add to the forward gain just as the director 101 andreflector 100 on the shaded dipole 96 adds to the gain by beingspacephased coupled thereto. The overall gain of the antenna array 95has been measured to be approximately sixteen db over the tuned dipole97.

Although this invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred forin has been made only by Way of exampleand that numerous changes in the details of construction and thecombination and arrangement of parts may be resorted to withoutdeparting from the spirit and the scope of the invention as hereinafterclaimed.

'What is claimed is:

1. An antenna comprising a driven element having a resonant frequencyand having two shunt elements coupled on opposite sides thereof andbeing resonant to higher and lower frequencies than said resonantfrequency, and two elements disposed on opposite ends of the drivenelement and having resonant frequency characteristics.

2. An antenna comprising a driven element having resonant frequencycharacteristics, two shunt elements voltage coupled to said drivenelement on opposite sides thereof and being resonant to higher and lowerfrequencies than said resonant frequency, and two elements spaced onopposite ends of and generally linear with the driven element and havingresonant frequency characteristics.

3. An antenna comprising a driven element and two shunt elements, saiddriven element being substantially resonant to a working frequency, saidshunt elements being positioned closer than .05 wave length from saiddriven element for voltage coupling therewith and coupled on oppositesides thereof, said shunt elements being resonant to higher and lowerfrequencies than said working frequency, and two elements on oppositeends of said driven element and having resonant frequencycharacteristics.

4. An antenna comprising first and second elements, one of said elementshaving end portions spaced apart substantially equal to the electricalhalf-wave length thereof, the other of said elements having end portionsspaced apart less than the electrical half-wave length thereof, the endportions of the second element being spaced from the first element andeffecting a coupling therewith, said coupling comprising a voltagecoupling which is greater than the radiated wave coupling, and feed lineconnections for one of said elements.

5. An antenna comprising first and second elongated elements, one ofsaid elements having a length substantially equal to the electricalhalf-wave length thereof, the other of said elements having a lengthless than the electrical half-wave length thereof, means forelectrically coupling the end portions of the first element to thesecond element, said coupling means comprising a voltage coupling whichis greater than the radiation wave coupling, and feed line connectionsfor one of said elements.

6. An antenna comprising first, second and third elongated elements, oneof said elements having a length substantially equal to the electricalhalf-wave length thereof, the remaining elements having a length lessthan the electrical half-wave length thereof, means for electricallycoupling the end portions of the first. and second elements to the thirdelement, said coupling means comprising a voltage coupling which isgreater than the radiation wave coupling, and feed line connections forone of said elements.

7. An antenna comprising first and second elements, said first elementhaving a length substantially equal to the electrical half-wave lengththereof, said first element having first and second coupling portions,the physical spacing between said first and second coupling portionsbeing less than the physical length thereof, said second element havingfirst and second coupling portions near the ends thereof and physicallyspaced apart less than the-electrical length of the second element, saidfirst coupling portions of said first and second elements being adjacentand said second coupling portions of said first and second elementsbeing adjacent and comprising a voltage coupling which is greater thanthe radiation wave v coupling therebetween.

8. An antenna comprising first and second elements, said first elementhaving a length substantially equal to the electrical half-wave lengththereof, said first element having first and second coupling portions,the physical spacing between said first and second coupling portionsbeing less than the physical length thereof, said second element havinga length varying from the electrical halfwave length thereof said secondelement having first and second coupling portions physically spacedapart less than the electrical half-wave length of the second element,said first coupling portions of said first and second elementscomprising a capacitive voltage coupling, said second coupling portionsof the first and second elements comprising a capacitive voltagecoupling, and one of said elements being driven.

9. An antenna comprising first, second, and third ele ments, said firstelement having a length substantially equal to the electrical half-wavelength thereof, said first element having first and second couplingportions, the physical spacing between said first and second couplingportions being less than the physical length thereof, said second andthird elements each having first and second coupling portions near theends thereof and having a physical length less than the electricalhalf-wave length thereof, said first coupling portions being adjacentand said second coupling portions being adjacent, each group i ments,said first element having a length substantially 1 equal to theelectrical half-wave length thereof, said first element having first andsecond coupling portions, the physical spacing between said first andsecond coupling portions being less than the physical length thereof,said second and third elements each having first. and second couplingportions physically spaced apart less than the electrical half-wavelength of the second and third elesee ers ments, respectively, saidfirst coupling portions of said first and second elements and of saidsecond and third elements comprising a'voltage coupling which is greaterthan the radiation wave coupling therebetween, said second couplingportions of the first and second elements and of said second and thirdelements comprising a voltage coupling which is greater than theradiation wave coupling thcrebetween, and one of said elements beingdriven.

11. An antenna comprising a dipole, an auxiliary element having firstand second ends and being connected together by an intermediateconductive portion, said first and second ends of said auxiliary elementspaced from said dipole and voltage coupled thereto at points thereon,the first and second ends of said auxiliary element being spaced apartwith respect to each other such that the impedance of the auxiliaryelement is of the same order as the impedance between said points onsaid dipole.

12. A11 antenna comprising a dipole, feed lines connected to said dipoleas a driven element, an auxiliary element having first and second endsand being connected together by a conductive intermediate portion, saidfirst and second ends being spaced closer than said intermediate portionto said dipole, said first and second ends of said auxiliary elementspaced from said dipole and volt age coupled thereto at points thereon,and the first and second ends of said auxiliary element being spaced fanther apart with respect to each other than the spacing of each of saidends relative to said dipole.

13. An antenna comprising first and second main elements, each saidfirst and second elements having inner and outer ends, said inner endsbeing more closely spaced than said outer ends, feed lines connected tothe inner ends of said main elements, an auxiliary element having firstand second ends connected together by an intermediate conductiyeportion, said auxiliary elements first an second ends being spacedcloser to said first and second main elements than the said intermediateportion is spaced to said main elements, said first and second ends ofsaid auxiliary element spaced from said main elements and voltagecoupled thereto at points thereon, and the first and second ends of saidauxiliary element being spaced apart with respect to each other agreater distance than the spacing thereof relative to said mainelements.

14. An antenna comprising a driven dipole, first and second elementseach having outer ends and an interme diate portion, said first andsecond elements being bent so that the physical length thereof is lessthan the electrical half-wave length thereof, the ends of said elementsbeing voltage coupled to said dipole, said dipole having generally aresonant length at a working frequency, said first and second elementsbeing resonant to higher and lower frequencies than said workingfrequency, said driven dipole and said first and second elements beingon generally opposite sides thereof in a given plane, and a directorelement resonant to a frequency higher than said working frequencyspacephase coupled to said driven dipole and disposed in said givenplane substantially parallel to said driven dipole.

15. An antenna comprising a driven dipole, first and second elementseach having outer ends and an intermediate portion, said first andsecond elements being bent so that the physical length thereof is lessthan the electrical half-wave length thereof, the ends of said elementsbeing voltage coupled to said dipole, said dipole having generally aresonant length at a working frequency, said first and second elementsbeing resonant to higher and lower frequencies than said workingfrequency, said driven dipole and said first and second elements beingon generally opposite sides thereof in a given plane, a director elementresonant to a frequency higher than said working frequency space-phasecoupled to said driven dipole and disposed in said given planesubstantially parallel to said driven dipole, and first and secondcollector elements disposed substantially in said given plane each withfirst and second ends with the first ends adjacent the ends of saiddriven dipole, the second ends of each of said collector elements lyingforward of said driven dipole, said collector elements lying generallyparallel to the adjacent portion of the line denoting the fieldintensity pattern in said given plane of the combined driven dipole andfirst and second elements when such pattern has a line denoting theforward gain spaced ahead of said driven dipole approximately 1.5wavelength, said collector elements being substantially resonant to saidworking frequency.

16. An antenna comprising a driven dipole, first and second elementseach having outer ends and an intermediate portion, said first andsecond elements having a physical length less than the electricalhalf-wave length thereof, the end portions of said elements beingvoltage coupled to said dipole, said dipole having generally a resonantlength at a working frequency, said first and second elements beingresonant to higher and lower frequencies than said working frequency,said driven dipole and said first and second elements being on generallyopposite sides thereof in a given plane, and first and second collectorelements disposed susbtantially in said given plane each with first andsecond ends with the first ends adjacent the ends of said driven dipole,the second ends of each of said collector elements lying forward of saiddriven dipole, said collector elements being substantially resonant tosaid working frequency.

17. An antenna comprising a driven dipole, first and second elementseach having outer ends and an intermediate portion, said first andsecond elements being bent so that the physical length thereof is lessthan the electrical half-wave length thereof, the ends of said elementsbeing voltage coupled to said dipole, said dipole having generally aresonant length at a working frequency, said first and second elementsbeing resonant to higher and lower frequencies than said workingfrequency, said driven dipole and said first and second elements beingon generally opposite sides thereof in a given plane, first and secondcollector elements disposed substantially in said given plane each withfirst and second ends with the first ends adjacent the ends of saiddriven dipole, the second ends of each of said collector elements lyingforward of said driven dipole, said collector elements beingsubstantially resonant to said working frequency, a high frequencyresonant director and a low frequency resonant reflector disposedforward and rearward of each of said collector elements in said givenplane, said directors and reflectors being space-phase coupled to therespective collector elements.

18. An antenna comprising a driven dipole, first and second elementseach having outer ends and an intermediate portion, said first andsecond elements being bent so that the physical length thereof is lessthan the electrical half-wave length thereof, the ends of said elementsbeing voltage coupled to said dipole, said dipole having generally aresonant length at a working frequency, said first and second elementsbeing resonant to higher and lower frequencies than said workingfrequency, said driven dipole and said first and second elements beingon generally opposite sides thereof in a given plane, a director elementresonant to a frequency higher than said working frequency space-phasecoupled to said driven dipole and disposed in said given planesubstantially parallel to said driven dipole, first and second collectorelements disposed substantially in said given plane each with first andsecond ends with the first ends adjacent the ends of said driven dipole,the second ends of each of said collector elements lying forward of saiddriven dipole, said collector elements lying generally parallel to theadjacent portion of the line denoting the field intensity pattern insaid given plane of the combined driven dipole and first and secondelements when such pattern has a line denoting the forward gain spacedahead of said driven dipole approximately 1.5 wave lengths, saidcolaseasrs lector elements being substantially resonant to said workingfrequency, and a high frequency resonant director and a low frequencyresonant reflector disposed forward and rearward of each of saidcollector elements in said given plane, said directors and reflectorsbeing spacephase coupled to the respective collector elements, eachgroup of reflector, collector element and director lying in a pathgenerally parallel to the front-to-rear path defined by said drivendipole and said director element.

19. An antenna comprising a driven dipole, first and second elementseach having outer ends and an intermediate portion, said first andsecond elements being bent so that the physical length thereof is lessthan the electrical half-wave length thereof, the ends of said elementsbeing voltage coupled to said dipole, said dipole having generally aresonant length at a working frequency, said first and second elementsbeing resonant to higher and lower frequencies than said workingfrequency, said driven dipole and said first and second elements beingon generally opposite sides thereof in a parallel to the adjacentportion of the line denoting the field intensity pattern in said givenplane of the combined driven dipole and first and second elements whensuch pattern has a line denoting the forward gain spaced ahead of saiddriven dipole approximately 1.5 Wave lengths, said collector elementsbeing substantially resonant to said working frequency, and additionalcollector elements substantially resonant to said working fre queney andeach having a near end and a far end with said near ends disposedadjacent the ends of said driven dipole and lying spaced from and at anacute angle to said given plane and lying in planes passing through saidfirst and second collector elements with said last mentioned planessubstantially perpendicular to said given plane.

20. In combination, a dipole, and an elongated element resonant to afrequency lower than that of said dipole and voltage coupled near itsends to said dipole.

21. In combination, a dipole, and an elongated element resonant to afrequency higher than that of said dipole and voltage coupled near itsends to said dipole.

22. An antenna comprising, a driven element having a resonant frequency,and a shunt element voltage coupled on one side thereof and havingresonant frequency characteristics different from that of said drivenelement.

23. An antenna comprising, a driven element having a resonant frequency,a shunt element voltage coupled on one side thereof and having resonantfrequency characteristics different from that of said driven element,and two elements generally linearly disposed on opposite ends of thedriven element and having substantially resonant frequencycharacteristics.

24. An antenna comprising, a driven element and two shunt elements, saiddriven element being substantially resonant to a working frequency, saidshunt elements being positioned closer than .05 wave length from saiddriven element for voltage coupling therewith and coupled on oppositesides thereof, and said shunt elements having resonant frequencycharacteristics higher and lower than said working frequency.

25. An antenna comprising, first and second elements, one of saidelements having end portions spaced apart more than the electricalhalf-wave length thereof, the other of said elements having end portionsspaced apart less than the electrical half-wave length thereof, andmeans eifecting a voltage coupling with said end portions which isgreater than the radiated wave coupling.

26. An antenna comprising, first and second elements, one of saidelements having end portions spaced apart more than the electricalhalf-wave length thereof, the other of said elements having end portionsspaced apart less than the electrical half-wave length thereof, anddipole means having portions efiecting a voltage coupling with said endportions which is greater than the radiated wave coupling.

27. An antenna comprising, first and second elongated elements, one ofsaid elements having a length substantially equal to the electricalhalf-wave length thereof, the other of said elements having a lengthless than the electrical half-wave length thereof, and means for voltagecoupling the end portions of the first element to the second element.

28. An antenna comprising, first and second elongated elements, one ofsaid elements having a length substantially equal to the electricalhalf-wave length thereof, the other of said elements having a lengthgreater than the electrical half-wave length thereof, and means forvoltage coupling the end portions of the first element to the secondelement.

References Cited in the file of this patent UNITED STATES PATENTS Re.23,273 Kearse Sept. 26, 1950 2,505,115 Hills et al. Apr. 25, 19502,572,166 Lorusso Oct. 23, 1951 2,578,973 Hills Dec. 18, 1951 2,580,798Kolster Jan. 1, 1952 2,640,933 Spindler June 2, 1953 2,789,286 MarshallApr. 16, 1957 FOREIGN PATENTS 146,302 Germany July 14, 1901

